The Greenland glacial board

Viking Eric Red named this land in X century green, but white colour prevails here. On the glaciation area Greenland takes the second place in the world after Antarctica and consequently so the island role as polygon for basic research of glaciers is considerable, including their deep drilling. Glaciologists, studying samples from deep horizons, judge morphology and dynamics of a glacier, microbiologists - about ancient life, millenia held down in ice. But it is most important, perhaps, paleoclimate aspect of researches. Accumulating air incorporations of times of the formation, deep ice layers store the unique information on past atmosphere. On an isotope compound of ice in its continuous columns received in Antarctica and Greenland, traces a minimum of four cycles of global warmings and cold snaps for last 400 thousand years are discovered. All is scientific results. But deep drilling in ices can have and practical value - for search of the minerals hidden by glaciers.

Greenland - the greatest island of the world, which area compounds 2.18 million км2. It is had between Arctic ocean and northern part of Atlantic. In administrative - the political attitude Greenland - the part of Kingdom of Denmark, geographically concerns the North America. As a result of an overall cold snap 3 - 2 million years ago the island began to become covered by the powerful ice layer which has gradually occupied all its surface. At the subsequent warming glaciation degradation, and now ices has begun occupy 1.83 million км2, or nearly so 85 % of terrain of island.

The main source of accumulation of snow in the Greenland glacial board - a hard atmospheric precipitation: snow, snow groats, a hailstones. In core area never happens meltings, and the snow layers accumulated year after year, are dipped on the increasing depth where under the influence of the overlying condensing and turn to acinose ice - firn. To augmentation of depth under the influence of increasing pressure there is a complete closure of its air pores, and firn becomes ice soil.

In the central part of the Greenland board snow - firn the strata extends on depth to 75 - 77 m, more low, on many hundreds metres, - ice. Its average thickness - 1790 m, maximum - 3416 m. If ice of Greenland has thawn, level of the World ocean has raised on 7.5 m.

The surface of a glacial board hollow raises from shores into the depth islands, reaching in the central part of height of 3.3 km above sea level. Under the central part of a glacial board the extensive plain bordered from east and western sides with a belt of mountain chains is had. And 20 % of a total area of a bed of a glacial integument are below a sea level.

In entrails of Greenland, in terrains, free from ice, considerable reserves of graphite, hard coal, lead - zinc and iron ores (the large deposit of last is particulate latent by a glacier), the minerals rich with chrome, molybdenum, uranium are discovered.

In offshore areas of Greenland people lived at least throughout last millenium, but the history of research of a glacial integument is rather short. Its serious analysis has begun only in the end of XIX century. N.Nordensheld who has driven in 1870 deep into islands on 50 km, and in 1883 - on 117 km was the first who was convinced that is a continuous integument.

In 1888 F.Nansen and O.Sverdrup have crossed on skis a southern part of Greenland, and four years after R.Piri - northern. The next years it repeatedly made expeditions on a glacial integument, and in 1900 the first has reached northern coast. In the beginning of XX century in routeing researches of a glacial board data on geography of island and behaviour of a glacier collected. In 1929 - 1931 German geophysicist A.Vegener has organised two stationary stations approximately on 71 ° N - one in the centre of a glacial board, another at the western coast. By means of seismic devices a thickness of a glacier for the first time has been defined, regular measurements of accumulation of snow are organised, the constitution snow - firn of region is studied.

During the Second World War, after occupation of Denmark, Greenland has appeared cut off from mother country, and in 1941 of the USA have established military protectorate over this terrain, having obliged to abandon island after the end of war. However it has not descended: in 1951 it has been concluded Danish - the American agreement “About defence of Greenland”, and the American armies are in island terrain till now.

In post-war years the greatest attention here was given to building of airdromes on ice, to the device of stationary and seasonal bases and camps, a lining of lines etc. In connection with complexity and dearness these operations were conducted not only the relaxed war by Denmark, but also France, the Great Britain and the USA.

Large scientific results were brought by the French polar expedition under the guidance of Victor. In 1948 - 1951 its groups some times crossed a glacier. Seismic operations have allowed to compound detailed enough relief map of a bed spreading a glacier. The French polar explorers have appeared the first who has extracted deep samples of ice. Around seasonal camps “Camp VI” and “Centrale” (the western and central part of Greenland) by means of a serial prospecting drilling equipment two wells by depth of 126 and 150 m. are drilled

In 1954 in Denmark the Arctic institute which is engaged mainly in coordination scientifically - research operations in Greenland is created, and in two years the International Greenland expedition which has united scientists of Denmark, France, Switzerland, Austria and Germany is based. Its forces in 1959 had been based a glaciological hospital “Yarl jose” on east slope of a glacial board, its triangulation, radar-tracking sounding of a glacial strata etc. is spent